Its from the wheel wells. Check the front and rear wheel wells. It was sprayed on from the factory.

Yup, factory undercoating.

Yup.

thanks for clearing this up, a big relief! been weighing on my mind. Do I clean this sh**t up, or do I say, forgetttaboutit....

It'll come off. Hard part is removing it without removing the paint. The color under the car is mostly just overspray, no clear coat, so it comes off pretty easy if you scrub it.

If you want it off, something that's worked for me is soaking it with trans fluid or parts washer solvent and gently wiping it.

Thanks for your help guys. I'll probably leave it on there. My goal with the car is to keep as much from the factory as possible and/or period correct while keeping it driveable. Trying to make a time capsule out of this one. it would be a blast to pick up another Formula and make it a modern day street car, but I have another project waiting that will likely supersede that dream.

Factory random sloppiness is hard to faithfully reproduce. With that said, I've had some luck removing stuff like that with a claybar.

The word "claybar" will be triggering jokes around here, forever!

Claybar is good, but not that good!

There was a belt dressing back in the 90's that would also leave splatter like that inline with the belts-- but I think the under coating is what you see here.

might try removing it with mineral spirits, it might cut it without removing paint. I would definitely check somewhere inconspicuous on a Q-tip before I tried it tho...

But again, anything you do will make a smeary mess, and then you have to clean that up too... I would leave it alone personally, unless you are planning on repainting the area anyway.

John